Prior art protective suits, whether chemical, biological, physical, armor, etc., inhibit or completely prevent the human (or animal) body's natural cooling mechanism, perspiration, from functioning, which leads to overheating, exhaustion, loss of cognitive function, and eventually death. The disclosed personal artificial transpiration cooling system cools the human (or animal) inside a protective suit to extend the amount of time that human (or animal) can function at a high physical and cognitive level inside the suit. Furthermore, the disclosed personal artificial transpiration cooling system preferably provides this cooling capability in a highly portable manner that does not require external power sources (such as batteries and/or a motor) and their accompanying weight. This cooling capability mimics that of natural perspiration and can even utilize sweat generated by the wearer. Providing an internal environment that removes sweat and provides passive cool temperatures (with preferably noiseless and vibration free operation) will reduce related discomfort, thereby reducing distraction and improving cognitive focus on the wearer's intended task.
A prior art personal cooling system developed at Stanford University and licensed to Avacore (see www.avacore.com) entails cooling a person with liquid water while applying a vacuum to the person's hand. Their system, while effective at rapidly cooling a person, requires an external power supply to achieve the vacuum and circulate the water. This requires power input from an external source (making this scheme not human-portable or impairing mobility) or power input from a human, requiring the energy and attention of the wearer or another individual (making this scheme unsuitable for extended, continuous usage). See also US Patent Publication 2002/0007201 dated Jan. 17, 2002.
The prior art of artificial transpiration includes Wheeler and Strook “The transpiration of water at negative pressures in a synthetic tree”, Nature vol. 455, pp. 210-212 (2008) where they demonstrate a system for artificial transpiration using hydrogel membranes. This document does not describe artificial stomata and is therefore limited to operation in environments from 85%-100% relative humidity. At lower relative humidity, cavitation will occur and the system will no longer function. See also Wheeler and Strook, “The Transpiration of Water at Negative Pressures in a Synthetic Tree—Supplementary Information”—Nature 10.1038/nature07226.